1. Field of the Invention
The present invention relates to firearms and, in particular, concerns a system and method of converting the caliber of an automatic pistol from a first caliber to a second and also an improved sight system.
2. Description of the Related Art
Automatic pistols are very well known. Many of these pistols comprise a frame that houses a trigger assembly and a magazine. A spring biased, movable slide assembly is then mounted on top of the frame. The slide includes a housing, a firing chamber, a firing pin assembly and a barrel. In operation, the user pulls the trigger which induces the firing pin assembly to strike a cartridge in the chamber, causing the cartridge to fire, resulting in the slug or projectile(s) travelling down the barrel. With slide based pistols, the detonation of the cartridge also results in the slide housing recoiling backwards over the frame and barrel and to then slide forward back into the shooting position as a result of the spring biasing of the slide housing. This backwards and forwards motion of the slide housing performs several functions, including ejecting the spent cartridge casing, cocking the firing pin assembly and loading another cartridge into the chamber when the slide housing comes forward.
Typically, slide assemblies are specific to a particular pistol and allow the shooter to only shoot the caliber of bullet that the barrel, magazine and firing chamber are sized to receive. However, it is often desirable for shooters to be able to practice shooting with less powerful and/or less expensive ammunition. While slide assemblies on many pistols are removable, the easy interchangeability of the slide assemblies is limited.
More specifically, some pistols, such as those manufactured by Glock Ges.m.b.H. of Austria are designed to be modular such that the various components, e.g., the slide assembly, the magazine, the trigger assembly, etc., can be easily removed from the frame of the pistol. However, while removing a slide and a magazine is relatively easy with Glock™ pistols, changing the slide and magazine to a different caliber is more complicated.
For example, it is often desirable to be able to fire low power and inexpensive .22 caliber ammunition in more powerful, higher caliber pistols. The lower power .22 caliber ammunition allows a shooter to become familiar with the feel of the pistol while shooting a round that has less recoil and is considerably cheaper than larger pistol calibers. Moreover, the reduced power of the smaller .22 caliber ammunition allows it to be shot at smaller range facilities and the like.
However, switching to a smaller round like a .22 caliber is complicated by the fact that the smaller caliber may not have sufficient power to cycle the slide housing back and forth over the frame. Moreover, many slide pistols, such as Glock™ pistols are designed such that the barrels pivot with respect to the slide housing so as to facilitate loading of the next round in the magazine. Often smaller caliber cartridges, such as the .22 caliber, produce insufficient recoil of the slide assembly to both cycle the slide housing over the frame and pivot the barrel with respect to the slide housing to load the next cartridge in the magazine into the firing chamber.
Some efforts have been made by others to address this issue by designing the magazine to spring load the next cartridge in line with the firing chamber such that the firing chamber and barrel do not pivot with respect to the slide. In these products, the barrel and firing chamber slide straight back and the spring loaded magazine urges the next cartridge into the firing chamber when the firing chamber is exposed to the magazine. This requires that the barrel and firing pin assembly move in a straight line with respect to the slide and frame.
To achieve the straight line motion of the barrel assembly with respect to the slide housing, the prior art product incorporates a guide that is engaged with the housing of the trigger assembly. The guide member and the trigger assembly are interconnected in such a way that the barrel and firing pin assembly cannot be removed from slide housing without the removal of the firing pin assembly. Alternatively, in some prior art products, the guide member has to be interconnected to the barrel assembly which complicates the installation and removal process.
This complicates the process of disassembling the converted barrel which further complicates cleaning of the components of the replacement slide assembly and the complexity of interaction between the components of the conversion slide makes the conversion slide potentially less reliable and more expensive Thus, there is a need for an improved conversion slide assembly for slide based semi-automatic pistols.
A further difficulty with both original and replacement slide assemblies and firearms in general is that the assemblies do not accommodate aftermarket sight assemblies in a convenient fashion. Most slide assemblies include fixed iron sights at the front and rear of the slide housing. It is often desired to replace the iron sights with other aftermarket sights. Often, the original rear sight is simply positioned within a groove extending across the width of the housing. By moving the original rear sight from left to right, the shooter can adjust the point of aim of the rear sight.
Similarly, when the user wishes to replace the rear sight with an aftermarket sight, the aftermarket sight is positioned within the same groove and must be adjusted back and forth to the correct position. Thus, any change between sights requires that the pistol be re-sighted by the shooter. Alternatively, the shooter can place the replacement sight on the housing above the original sight but this results in the aftermarket sight not replicating the sight picture of the original sight which can affect shooting performance. Hence, there is also a need for a slide assembly, and firearms in general, that facilitates easier interchangeability between sights.